Hermes — AI Coding Agent for VS Code

Hermes is an AI coding agent that runs directly in your VS Code sidebar. It streams responses in real time, executes tools, manages sessions, and tracks live context usage through the Hermes CLI over the Agent Client Protocol (ACP).

Features

Chat & Streaming

• Sidebar chat panel — Hermes lives in the VS Code activity bar with a custom winged sandal icon
• Streaming markdown — responses render live with debounced markdown formatting and DOMPurify sanitization
• Thinking display — extended reasoning shown as gold italic status line
• Inline images — cached Hermes media renders directly in chat without exposing arbitrary local paths
• Copy buttons — hover any code block to copy its contents

Tools & Skills

• Claude Code-style tool display — tool calls show with bold kind labels (Read, Edit, Bash, Search, Fetch) and file paths from ACP locations
• Status icons — ✓ green (done), ⋯ gold (running), ✗ red (error)
• Live file integration — edited files auto-open in VS Code editor; read files open as preview tabs
• Skills picker — ✦ button dynamically loads 100+ skills from ~/.hermes/skills/, grouped alphabetically
• Todo progress overlay — persistent checklist appears when Hermes uses its todo tool

Context & Attachments

• IDE context awareness — active file, selection, and open tabs automatically sent with each message
• File attachment — ⊞ button, drag & drop from explorer, or Ctrl+V to paste images
• Multiple attachments — files accumulate as chips, all cleared after send
• Path references — attached files sent as paths (not content), Hermes reads on demand

Sessions

• Persistent sessions — conversations stored in VS Code workspaceState, survive reloads
• Session picker — click the session name to switch, create, rename (✎), or delete (✕)
• Auto-titled — first user message becomes the session title
• ACP session resume — stored session IDs allow Hermes to resume context across restarts
• Title sync — renaming sends /title to Hermes for persistence in its session DB

Model Switching

• Multi-provider — Anthropic Claude + OpenAI Codex models in grouped picker
• Provider:model syntax — seamless provider switching via /model anthropic:claude-opus-4-6
• Dynamic catalog — reads from ~/.hermes/models_dev_cache.json with hard-coded fallbacks

Queue & Interrupt

• Queued prompts — send follow-ups while Hermes is busy
• Interrupt mode — new messages cancel the current turn (matches Hermes TUI busy_input_mode: interrupt)
• Visual feedback — logo pulses gold, input border glows while agent is working

Status & Tokens

• Session name + token counter fill the top status bar
• Gold current tokens — e.g. 45.2k / 1M with progress bar
• Color warnings — gold at 70%, red at 90% context usage
• Bottom toolbar — model picker, file/skill attach, slash command buttons

Requirements

• Hermes CLI installed (pip install hermes-agent)
• Hermes authenticated (hermes setup)
• For Remote SSH: extension runs on the workspace/server side where Hermes is installed

Getting Started

1. Install Hermes: pip install hermes-agent
2. Authenticate: hermes setup
3. Install the .vsix file (Extensions → ... → Install from VSIX)
4. Open the Hermes panel from the Activity Bar (winged sandal icon)
5. Start chatting

Extension Settings

Keyboard Shortcuts

Commands

Slash Commands

Architecture

Extension Host (Node.js, runs on workspace/server side)
├── extension.ts      — activation, AcpClient + SessionManager + ChatPanelProvider
├── acpClient.ts      — JSON-RPC 2.0 over stdio (hermes acp subprocess)
├── sessionManager.ts — session lifecycle, streaming dedup, tool/todo extraction
├── chatPanel.ts      — WebviewViewProvider, HTML/CSS, session persistence, file integration
├── modelCatalog.ts   — dynamic model menu from Hermes cache
└── skillCatalog.ts   — skill loader from ~/.hermes/skills/

Webview (Browser sandbox)
└── webview/main.ts   — streaming renderer, markdown, session/model/skills UI

The extension spawns hermes acp as a subprocess and communicates via JSON-RPC 2.0 over stdio. File edits and reads auto-open in VS Code. The webview is sandboxed with CSP and DOMPurify for agent content, cached media is isolated to extension storage, and permission requests are confirmed in VS Code before approval.

License

MIT